/**
 * API fetch wrapper for Scenar Creator.
 */

const API = {
    async post(url, body, isJson = true) {
        const opts = { method: 'POST' };
        if (isJson) {
            opts.headers = { 'Content-Type': 'application/json' };
            opts.body = JSON.stringify(body);
        } else {
            opts.body = body; // FormData
        }
        const res = await fetch(url, opts);
        return res;
    },

    async postJson(url, body) {
        const res = await this.post(url, body, true);
        if (!res.ok) {
            const err = await res.json().catch(() => ({ detail: res.statusText }));
            throw new Error(err.detail || 'API error');
        }
        return res.json();
    },

    async postBlob(url, body) {
        const res = await this.post(url, body, true);
        if (!res.ok) {
            const err = await res.json().catch(() => ({ detail: res.statusText }));
            throw new Error(err.detail || 'API error');
        }
        return res.blob();
    },

    async postFormData(url, formData) {
        const res = await this.post(url, formData, false);
        if (!res.ok) {
            const err = await res.json().catch(() => ({ detail: res.statusText }));
            throw new Error(err.detail || 'API error');
        }
        return res.json();
    },

    async get(url) {
        const res = await fetch(url);
        if (!res.ok) throw new Error(res.statusText);
        return res.json();
    },

    downloadBlob(blob, filename) {
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = filename;
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        URL.revokeObjectURL(url);
    }
};